I went through that same thinking with bedding which of course is supposed to be washed weekly. Then when I didn't feel like doing it one week it occured to me that they only nap in it 2 hours times 5 days or a total of 10 hours a week, and it airs out in between. That is only equivalent to one nights sleep at home. You can bet most parents don't change their child's bedding daily so why do we. Monthly is working so much better for me. Usually I do pillowcases weekly and all bedding monthly. I know not the norm but have had no issues. Also we do outside play at the end of the day so it isn't like they are bringing sand or ants into the beds with them either.